tasks a-s

Task/Permutations/OCaml/permutations-3.ocaml

@@ -0,0 +1,17 @@
+let rec pr_perm k n l =
+   let a, b = let c = k/n in c, k-(n*c) in
+   let e = List.nth l b in
+   let rec sub e = function
+      | [] -> failwith "sub"
+      | h :: t -> if h = e then t else h :: sub e t in
+   (Printf.printf " %d" e; if n > 1 then pr_perm a (n-1) (sub e l))
+
+let show_perms l =
+   let n = List.length l in
+   let rec fact n = if n < 3 then n else n * fact (n-1) in
+   for i = 0 to (fact n)-1 do
+      pr_perm i n l;
+      print_newline()
+   done
+
+let () = show_perms [1;2;3;4]